In recent years, it has been disclosed that the electric wave characteristics of electromagnetic waves can be controlled by periodically arranging a conductive body pattern having a specific structure (hereinafter, referred to as a meta-material). More specifically, a meta-material that is configured so as to suppress the propagation of the electromagnetic waves in a specific frequency band is called an electromagnetic band gap structure (hereinafter, referred to as an EBG structure).
As a technique of such a type, for example, there is a technique described in Patent Document 1 (U.S. Pat. No. 6,262,495 Specification). In FIG. 2 of Patent Document 1, a structure, that is, a so-called EBG structure of a mushroom type is illustrated, in which a plurality of island-shaped conduction elements is arranged on the upper side of a sheet-shaped conduction plane, and each of the island-shaped conduction elements is connected to the conduction plane as a via.